This invention relates generally to devices for rearward viewing from vehicles such as passenger cars, trucks, or the like. The invention is more particularly concerned with video camera and viewing screen systems which can provide a driver or other vehicle operator a view of traffic conditions to rearwards, at least from right and left sides of the vehicle.
Conventionally, passenger vehicles and trucks are provided with outside mirrors disposed at the left (driver) side and right (passenger) side of the vehicle, and in most cases with a rear view (center) mirror providing a view through the rear windscreen. These mirrors are necessary for safe vehicle operation and give the driver a view of traffic conditions behind the vehicle. The views from the right and left outside mirrors are especially useful to detect another vehicle in an adjacent lane, if the operator is planning to make a lane change or turn.
These conventional mirrors have a number of drawbacks. For example, in order to look at the rearward traffic conditions in the right side mirror, the operator has to take his or her eyes off the road ahead and instead divert his or her attention onto the small view provided by the outside mirror. This is often done even while traffic conditions ahead are rapidly changing. However, for safe vehicle operation the need to divert one's attention from the road should be minimized. Also, the outside mirror adjustment depends on the operator position, and so if the driver adjusts the seat upwards or downwards, or back or forth, the outside mirrors also have to be readjusted.
Adjusting the mirrors in traffic can be a dangerous maneuver. Also, objects or passengers in the vehicle can often block the driver's views through the center rear view mirror and the view of the right outside mirror.
Further, because the mirrors are positioned to be in line with the driver's position, the driver's view in the outside mirrors does not always reveal another vehicle in an adjacent lane and even with the rear of the vehicle (i.e., in a so-called blind spot). This occurrence of blind spots in the rear view mirrors and outside mirrors has been an ongoing problem.
The outside mirrors also produce significant amount of wind drag, because they project a substantial distance sideways from the vehicle. These mirrors are also subject to damage if the vehicle is driven or parked where there is only a small amount of sidewards clearance.
Another problem with conventional mirrors arises during night-time operation. If another vehicle is approaching from the rear or overtaking, the mirrors reflect glare from that vehicle's headlights directly at the driver of the leading vehicle. Even if the other vehicle dims its lights, the amount of light reflected in the driver side outside mirror can produce enough glare to cause momentary night blindness. Shades or tinted glass can help to reduce glare, but these can also impair the normal rearward view.
A number of proposals have appeared in recent times for supplementing a vehicle operator's view by use of a video camera mounted somewhere on the vehicle. These have generally involved mounting video cameras in box-like housings carried on arms that project from the vehicle. Typical of these are the arrangements described in U.S. Pat. Nos. 5,027,200; 4,910,591; and 3,689,695. Video viewing arrangements for viewing from the rear of a tractor trailer are described in U.S. Pat. Nos. 4,214,266 and 4,277,804. A camera arrangement from guiding a tractor or other farm vehicle is described in U.S. Pat. No. 4,288,814. These previous proposals do not suggest any practical solution to the problems encountered with conventional outside mirrors.